Irrigation and Drainage Engineering

Question 1

artificial application of water to the soil necessary to supply the moisture essential for plant growth.

Answer 1

Irrigation

Question 2

removal of excess water from the soil that is detrimental to plants.

Answer 2

drainage

Question 3

art of measuring horizontal and vertical distances between objects, of measuring angles between lines, of determining the direction of lines, and of establishing points by predetermined angular and linear measurements.

Answer 3

surveying

Question 4

a natural process of adding moisture to the soil but it can result to excessive water

Answer 4

rainfall

Question 5

determined from the data of the survey

Answer 5

Distances, angles, directions, locations, elevations, areas, and volumes

Question 6

portrayed graphically by the construction of maps, profiles, cross sections, and diagrams

Answer 6

survey data

Question 6

consists of counting the number of steps or paces in a required distance.

Answer 6

Distance by Pacing

Question 7

Made to lay out, locate and monitor public and private engineering
works.

Answer 7

Construction Survey

Question 7

type of surveying that takes into account the true shape of the earth. These surveys are of high precision and extend over large areas.

Answer 7

Geodetic Surveying

Question 7

Made to gather data to produce a topographic map showing the configuration of the terrain and the location of natural and man-made objects

Answer 7

Topographic Survey

Question 7

The survey of bodies of water made for the purpose of navigation, water supply, or sub-aqueous construction.

Answer 7

Hydrographic Survey

Question 8

type of surveying in which the mean surface of the earth is considered as a plane, or in which its spheroidal shape is neglected, with regard to horizontal distances and directions.

Answer 8

plane surveying

Question 9

Made to establish the horizontal and vertical positions of arbitrary points.

Answer 9

control survey

Question 10

Made to utilize the principles of aerial photogrammetry, in which measurements made on photographs are used to determine the positions of photographed objects.

Answer 10

Photogrammetric Survey

Question 10

Made to determine the length and direction of land lines and to establish the position of these lines on the ground

Answer 10

Boundary Survey

Question 10

Made to control, locate and map underground and surface works related to mining operations.

Answer 10

Mining Survey

Question 11

equivalent to two paces or a double step.

Answer 11

stride

Question 11

provides a rapid means of determining horizontal distances.

Answer 11

Stadia Method

Question 11

The equipment for stadia measurements consists of a telescope with horizontal hairs called stadia hairs and a graduated rod called

Answer 11

stadia rod

Question 11

The most commonly used devices are odometer, measuring wheel, and the optical rangefinder, these are called______

Answer 11

Distance by Mechanical Devices

Question 11

the process of determining the extent, size or dimensions of a particular quantity in comparison to a given standard. In surveying, __________ are usually concentrated on angles, elevations, times, lines, areas and volumes.

Answer 11

measurements

Question 11

a comparison of the measured quantity with a standard
measuring unit or units employed for measuring a quantity of that kind.

Answer 11

Direct measurements

Question 11

controls, topographic, and construction surveys necessary for the location and construction of highways, railroads, canals, transmission lines, and pipelines.

Answer 11

Route Survey

Question 11

based on the optical geometry of the instruments employed and is an indirect method of measurement

Answer 11

Distance by Tachymetry

Question 11

unknown distances may be determined through their relationship with known distance geometrically. These methods are widely employed in plane table surveys, and in triangulation work.

Answer 11

Distance by Graphical and Mathematical Methods

Question 11

is a simple device that can be attached to a wheel for purposes of roughly measuring surface distance. It is similar in function to the distance recorder of a vehicle speedometer

Answer 11

odometer

Question 11

defined as an angle subtended by an arc of a circle having length equal to the radius of the circle

Answer 11

radian

Question 11

the process of directly or indirectly measuring vertical distances to determine the elevation of points or their differences in elevation.

Answer 11

Leveling

Question 11

when it is not possible to apply a measuring instrument directly to a quantity to be measured an __________ is made

Answer 11

Indirect measurements

Question 11

refers to the measurement of images on a photograph. The type of photographs used are those taken from an aircraft with the axis of the camera pointed vertically towards the terrain photographed

Answer 11

Distance by Photogrammetry

Question 11

very similar in operation to an odometer except that it is more portable and self-contained measuring device. It is basically consists of a small wheel which is attached to a rod and handle, and can be pushed by an operator.

Answer 11

Measuring Wheel

Question 11

Tachymetric measurements are performed either by ______ method or the _____ method

Answer 11

stadia, subtense bar

Question 11

most common method of measuring or laying out horizontal distances. ______ consists of stretching a calibrated tape between two points and reading the distance indicated in the tape.

Answer 11

distance by taping (taping)

Question 11

used in design highways, railroads, canals, sewers, water supply systems; layout construction projects according to planned elevations;

Answer 11

Leveling results

Question 12

urved surface which is at any point perpendicular to the direction of gravity or the plumb line.

Answer 12

Level surface

Question 12

operates on the same principle as a rangefinder on a single-lens reflex camera. This device, which is usually hand-held or mounted on a small tripod, can be used to determine distances approximately simply by focusing

Answer 12

Optical Rangefinder

Question 13

a curved line in a level surface, all points of which are normal to the direction of gravity and equidistant from the center of the earth.

Answer 13

Level line

Question 14

a straight line in a horizontal plane which is tangent to a level line at one point.

Answer 14

Horizontal line

Question 14

a plane that is tangent to a level surface at a particular point.

Answer 14

Horizontal surface

Question 15

a fixed point of reference whose elevation is either known or assumed. They maybe permanent or temporary.

Answer 15

Bench Mark (BM

Question 15

at any point is a line parallel to the direction of gravity.

Answer 15

Vertical line

Question 16

an imaginary surface of the sea which is midway between high and low tides.

Answer 16

Mean sea level

Question 16

any convenient level surface coincident or parallel with mean sea level to which elevations of a particular area are referred.

Answer 16

datum

Question 16

are those which established at intervals throughout the country by the Philippine Coast and Geodetic Surveys (PCGS) or the Bureau of Lands.

Answer 16

Permanent BM

Question 17

the vertical distance between the two level surfaces in which the points lie.

Answer 17

Difference in elevation

Question 17

the vertical distance above or below mean sea level or any other selected datum

Answer 17

Elevation

Question 18

are those set up by the surveyor for his own use in a particular surveying project and may have assumed elevations.

Answer 18

Temporary BM

Question 18

the process of determining the difference in elevation between two or more points some distance apart.

Answer 18

Differential Leveling

Question 19

reading taken on a rod held on a point of known or assumed elevation. It is a measure of vertical distance from the established line of sight to the point sighted (+S).

Answer 19

Backsight (BS)

Question 20

used to establish changes in elevation along a line.

Answer 20

Profile Leveling

Question 20

an intervening point between two BMs upon which point foresight and backsight rod readings are taken to enable a leveling operation to continue from a new instrument position.

Answer 20

Turning Point (TP)

Question 21

a reading taken on a rod held on a point whose elevation is to be determined (-S).

Answer 21

Foresight (FS)

Question 21

is an electronic transit and an electronic distance measuring (EDM) combined into one instrument.

Answer 21

Electronic Total Station

Question 22

the aerial photos are prepared as a raster of pixels (picture elements), each of which has its raster row and column location and its density, stored digitally.

Answer 22

DPS (Digital Photogrammetric System)

Question 22

Common lines requiring surveying are ______

Answer 22

drains, roads, fences, and retaining walls

Question 22

the elevation of the line of sight of an instrument above or below a selected reference datum.

Answer 22

Height of Instrument (HI)

Question 23

used to measure distance using lasers. Laser range finders are called electronic distance measuring (EDM).

Answer 23

Range Finder

Question 23

The hydrologic cycle may be viewed as beginning with ________, the movement of water
from the liquid to the vapor state, from any wet surface

Answer 23

evaporation

Question 24

The system is based upon observations made on electromagnetic signals transmitted from a constellation of 24 satellites, each of which circling the earth in a precisely known orbit.

Answer 24

GPS (Global Positioning System)

Question 25

change of water from vapor to liquid

Answer 25

condensation

Question 26

change of vapor to ice

Answer 26

sublimation

Question 27

form clouds, which may, in turn, fall to earth

Answer 27

precipitation

Question 28

The precipitation may be dispersed in several ways: Be evaporated while falling _____

Answer 28

virga

Question 29

The precipitation may be dispersed in several ways: Be _______ by vegetation cover or by surfaces of buildings and other structures, and then be evaporated back into the atmosphere rather quickly

Answer 29

intercepted

Question 30

The precipitation may be dispersed in several ways: Water not intercepted by vegetation is
termed _______

Answer 30

throughfall

Question 31

The precipitation may be dispersed in several ways; Flow over the surface

Answer 31

overland flow

Question 32

The precipitation may be dispersed in several ways: discharge into streams and lakes

Answer 32

surface runoff

Question 32

The precipitation may be dispersed in several ways: move by evaporation into the atmosphere or by seepage towards the _______ or by further flow into the oceans

Answer 32

groundwater

Question 33

The precipitation may be dispersed in several ways: _____ through the ground surface to join existing soil water and be removed by evaporation from the soil, or by _____ towards stream channels (subsurface flow or _____), or by downward _______ to the underlying groundwater where it may be held from weeks to millennia.

Answer 33

Infiltrate, throughflow, interflow, percolation

Question 34

a gradual process in which something is changed from liquid to gas.

Answer 34

Evaporation

Question 34

the scientific study of the waters of the earth including their occurrence, distribution in space and time, and their relation to people and the natural environments

Answer 34

Hydrology

Question 35

biological process in which water evaporates from a plant, especially through tiny openings called stomata on the surfaces of leaves.

Answer 35

Transpiration

Question 35

a process by which vapor lose heat and changes into a liquid

Answer 35

Condensation

Question 35

rain, snow, or hails, all of which are formed by condensation of moisture in the atmosphere and fall to the ground.

Answer 35

Precipitation

Question 36

the combined process of transpiration by the plant, and evaporation from the soil or free water surface.

Answer 36

Evapotranspiration

Question 36

movement of water through the soil surface into the soil

Answer 36

Infiltration

Question 36

to make a liquid or gas pass through a porous substance.

Answer 36

Percolation

Question 36

a chemical process in which a solid substance is converted into a gas directly, without passing through an intermediate liquid phase.

Answer 36

Sublimation

Question 37

the horizontal transfer of a property such as heat, caused by air movement

Answer 37

Advection

Question 37

horizontal or lateral movement of water below the soil surface.

Answer 37

Seepage

Question 38

water not absorbed by the soil and flows into surface waters

Answer 38

Runoff

Question 39

paramount importance in the transformation of water from vapor to liquid or solid state and also in effecting favorable or unfavorable environmental conditions for man, animals or plants

Answer 39

Role of Climatological Elements

Question 39

amount of water that falls over the land or water bodies and is sometimes referred to as precipitation.

Answer 39

Rainfall

Question 39

water movement below the water table from groundwater storage to a channel or river.

Answer 39

Interflow

Question 39

movement of water underneath the soil surface from higher to lower elevation or pressure

Answer 39

Groundwater flow

Question 39

amount of invisible water vapour contained in the atmosphere, an important element in agriculture industry and human comfort. In combination with temperature and wind, the degree of moisture in the air determines the evaporation

Answer 39

Humidity

Question 39

water retained in potholes, small depressions and other land irregularities.

Answer 39

Overland storage

Question 39

is part of rainfall intercepted in plant body, physical structures, etc.; it is loss of water by direct evaporation.

Answer 39

Interception

Question 39

Subsurface components refer to those which become invisible – ____________. All these components occur below the ground surface.

Answer 39

infiltration, seepage, percolation and groundwater or aquifer flow

Question 39

degree of hotness or coldness of the environment as measured by air thermometer.

Answer 39

Temperature

Question 40

has chemical, microbiological and physical properties that determine its various functions

Answer 40

soil

Question 40

determines the rate of air drying and the layout or design of buildings.

Answer 40

Wind speed and direction

Question 40

these two elements are interrelated, the amount of solar radiation received by the earth’s surface is dependent upon sunshine duration. On the average, about _____ calories cm^-2 day^-1 is received by the earth’s surface and about 50% is used to vaporize water.

Answer 40

Solar radiation and sunshine duration, 400

Question 40

The amount of water the soil can hold depends upon the _______

Answer 40

physical properties

Question 40

a storehouse of plant nutrients, a habitat for bacteria, an anchorage for plants, and a reservoir of moisture needed by the plant.

Answer 40

soil

Question 41

different soil layers from top to bottom is referred to as _____.

Answer 41

soil profile

Question 42

the two most important physical properties of soil

Answer 42

Soil texture and soil structure

Question 43

relative proportion of various particles size groups of minerals. based on different combinations of sand, silt and clay particles

Answer 43

soil texture

Question 44

• after plowing, allow enough time for soil and air to interact before pre-irrigating
• return all possible organic matter to the soil
• plow below compacted layer, not at the same depth each layer
• follow a good crop rotation scheme

Answer 44

important practices to improve the soil structure of irrigated soils

Question 44

This property refers to the physical condition of the soil in relation to plant growth and ease of tillage. Soils in good tilth are crumbly, easily worked and readily take up water and dry.

Answer 44

Soil Tilth

Question 44

manner in which soil particles are arranged in group or aggregates. influences the rate at which water and air and move through the soil. It affects root penetration and soil nutrition.

Answer 44

soil structure

Question 45

For most soils with LOW ORGANIC MATTER content the value closely approaches an average of _____ and those with HIGH ORGANIC MATTER content the value may range from ________.

Answer 45

2.65, 1.5 to 2.0

Question 45

the attraction of water molecules to each other

Answer 45

Cohesion

Question 45

results of previous studies serves as the basis for empirical equations using climatic elements as variables. The type and accuracy of data available determine the suitable empirical equation for a given situation.

Answer 45

Effect of climate

Question 45

refers to the ratio of the density of a single particle to the density of a volume of water equal to the volume of the soil particle. It is also known as PARTICLE DENSITY

Answer 45

Real Specific Gravity (Rs).

Question 46

Three classes of water have been recognized depending upon the ease at which water is held by the soil

Answer 46

Gravitational water, Capillary water, Hygroscopic water

Question 46

the ratio of the weight of the given volume of dry soil, air space included, to the weight of an equal volume of water

Answer 46

Apparent Specific Gravity (As).

Question 46

water that moves freely downward under the influence of gravity through the larger soil pores.

Answer 46

Gravitational water

Question 46

measure of the forces with which the water is retained in the soil. It is normally expressed in atmospheres based on the average air pressure at sea level

Answer 46

Soil moisture tension

Question 47

also called volume weight of bulk density with a unit in grams per cubic centimeter or mass per unit volume.

Answer 47

Apparent Specific Gravity (As)

Question 47

the attraction of soil particles surface to water.

Answer 47

Adhesion

Question 48

influence the water holding capacity and the movement of water, air and roots through the soil.

Answer 48

Pore spaces

Question 48

This parameter represents the soil moisture content when the plants starts permanent wilting. It is the lower end of the available moisture range.

Answer 48

Permanent Wilting Point

Question 49

The soil moisture is generally considered to be ____ atmosphere for most soils.

Answer 49

15

Question 49

or insufficient water within the rootzone will greatly affect the performance of the plant.

Answer 49

Excessive water (waterlogging)

Question 49

refer to the portion of available moisture most easily extracted by plants which is approximately 75% of the available water or moisture

Answer 49

readily available moisture

Question 49

water present in smaller pores that moves slowly due to capillary forces and can move in any direction of greatest tension.

Answer 49

Capillary water

Question 49

water held so tightly on the particles and the surface that much of it is non-liquid and moves as vapor. It is not available for plant use.

Answer 49

Hygroscopic water

Question 49

The moisture content held between the field capacity and permanent wilting point is referred to as ______

Answer 49

available moisture or water

Question 49

parameter represents the threshold between gravitational water and capillary water._______ is the moisture content of the soil remaining after gravitational water has been removed

Answer 49

Field capacity

Question 49

Soil moisture tension is normally between _______ atmospheres when the soil is at field capacity.

Answer 49

0.1 and 0.3

Question 49

maximum amount that can occur for a given environmental condition in which the water is not limiting.

Answer 49

potential evapotranspiration (PET)

Question 50

process by which water is removed from the soil by a plant through the leaves and lost to the atmosphere.

Answer 50

Transpiration

Question 50

approximately
the difference between the soil moisture content at field capacity and wilting point

Answer 50

Total Available Water (TAW).

Question 50

refers to the sum total of transpiration through leaves of plants and evaporation from adjacent soil, water surfaces or from surfaces of the plant body.

Answer 50

Consumptive use

Question 50

the degree to which the amount of water in the soil is allowed to be depleted before the next irrigation is applied.

Answer 50

Management Allowed Deficit (MAD)

Question 50

the depletion of soil moisture below field capacity at the time that a particular soil moisture content, Pd, is measured.

Answer 50

Soil Moisture Deficit (SMD).

Question 50

the most crucial factor affecting surface irrigation. This single parameter essentially controls not only the amount of water entering the soil, also the advance rate of the overland flow

Answer 50

Infiltration

Question 50

Measurement and Monitoring of Soil Moisture

Answer 50

1. Gravimetric Method or Oven-drying Method
2. Feel and Appearance Method
3. Electrical Method
4. Tensiometer Method
5. Neutron Dispersion Method

Question 50

Consumptive use is sometimes referred to as

Answer 50

reference crop evapotranspiration (ETo)

Question 50

diffusion of water as a vapor surface from the surface into the atmosphere.

Answer 50

evaporation

Question 50

given by the so called crop coefficient which adjust the reference crop evapotranspiration to the actual crop ET.

Answer 50

Effect of crop characteristics

Question 50

complex process dependent on soil properties, physical properties, initial soil moisture content, previous wetting history, permeability changes due to the surface water movement, and air entrapment

Answer 50

Infiltration

Question 50

contains terms which account for plant type, plant growing period, mean temperature, and seasonal and latitudinal variations in theoretical solar radiation

Answer 50

Blaney-Criddle Equation

Question 50

these conditions and practices include variation of climate over time, size of fields, advection, soil water availability, cultivation method and other factors.

Answer 50

Effect of local conditions and agricultural practices

Question 50

an effective way of characterizing, evaluating and monitoring any irrigation system.

Answer 50

Water Balance

Question 50

If no rainfall occurs effective rainfall is _____.

Answer 50

zero

Question 50

ratio of water delivered to the farm to the water diverted from the source multiplied by 100

Answer 50

Water conveyance efficiency, Ec

Question 51

the ratio of water stored in the root zone during the irrigation to the water delivered to the farm multiplied by 100

Answer 51

Water application efficiency, Ea

Question 52

the ratio of water beneficially used by the plant to the water delivered multiplied by 100.

Answer 52

Water-use efficiency, Eu

Question 53

the ratio of water stored in the root zone during the irrigation to the water needed in the root zone prior to irrigation multiplied by 100.

Answer 53

Water storage efficiency, Es

Question 53

adaptable to rice lands where basins are constructed around one or more trees and flow turned into the basin by means of portable pipes or large hoses.

Answer 53

Basin flooding

Question 54

ratio of normal consumptive use of water to the net amount of water depleted from root zone.

Answer 54

Consumptive use efficiency, Ecu

Question 55

Surface Irrigation Methods are

Answer 55

1) Wild flooding
2) Controlled flooding
3) Check flooding
4) Basin flooding
5) border strip irrigation
6) Furrow irrigation

Question 55

widely used for irrigation of row crops

Answer 55

Furrow irrigation

Question 55

turning water onto natural slopes without much control or prior preparation such as those pastures and other inexpensive crops.

Answer 55

Wild flooding

Question 55

the ratio of the average numerical deviation in depth stored during irrigation to the average depth of water stored during irrigation

Answer 55

Water Distribution efficiency, Ed

Question 56

accomplished using field dikes or by use of BORDERS, CHECKS, and BASINS

Answer 56

Controlled flooding

Question 56

Type of ________ are some factors to consider when choosing a method of irrigation.

Answer 56

soil, topography, crop and economic considerations

Question 56

The important parameters in furrow irrigation are

Answer 56

a.) Length and slope of furrow
b.) Water distribution in furrows
c.) Furrow Stream Size

Question 56

Furrow length varies widely from LESS THAN _____ meters to MORE THAN ___ meters. The slope should preferably be ____ although some soils could have slope of 3 to 6 %.

Answer 56

25, 500, 0.5 to 3%

Question 57

a number of strips, 10-20 meters wide, are separated by low leeves perpendicular to the slope of the ground. Then the water is turned into the strips wetting the soil as it advances. Size of streams is delivered to a strip may vary from 15 to 300 li/sec depending on the kind of soil, size of the border and the nature of crop

Answer 57

border strip irrigation

Question 57

consist of turning water into relatively level plots surrounded by leaves as what is normally done for lowland rice production

Answer 57

Check flooding

Question 58

Corrugations or small furrows are simply narrow ditch between rows of crops with about _______ of surface area wetted during irrigation as compared to flooding method

Answer 58

0.2 to 0.5

Question 58

A typical sprinkler irrigation system consists of a pumping or pressure system, a main supply line, several lateral lines, vertical riser and sprinklers which can be ____

Answer 58

fixed nozzles or rotating type

Question 58

A typical sprinkler irrigation system consists of a _______, several ______ which can be fixed nozzles or rotating type

Answer 58

• pumping or pressure system, a main supply line,
• lateral lines, vertical riser and sprinklers

Question 58

The application of water in the form of spray over the land is accomplished by means of

Answer 58

sprinkler irrigation

Question 58

sprinkler can be used to control soil ______ and thus ensure FAVORABLE CONDITION for plants.

Answer 58

temperature and humidity

Question 58

also referred to as TRICKLE IRRIGATION it allows FREQUENT OR SLOW APPLICATION of water either directly on land surface or into the root zones of the crops.

Answer 58

Drip Irrigation Method

Question 58

The water outlets in the drip irrigation system are called ______ which DISCHARGE A FEW LITERS of water per hour.

Answer 58

emitters

Question 58

Subsurface irrigation method requires _____ water movement results in MORE EFFICIENT water application

Answer 58

upward

Question 58

applying water to the soil directly under the ground surface

Answer 58

Sub-irrigation Method

Question 58

structure located at the head of conveyance canals, main laterals and main farm ditches to control the flow of water

Answer 58

Headgate

Question 58

The major considerations for determining how much and when to apply irrigation water are: _____

Answer 58

amount of the water needed by the crop, availability of water, and soil moisture storage capacity

Question 58

Dam which may be an overflow type without spillway or storage type in which a spillway is an added component;
Gates, sluices, river training wall and other appurtenances.

Answer 58

Headwork structures

Question 58

______ affects every aspect of plant growth. It is the most important factor limiting crop productivity and yield.

Answer 58

Water stress

Question 58

a) Division boxes at head of laterals and sub-laterals;
b) Turnout to lateral and ditches

Answer 58

Control structures

Question 58

refers to the amount of water that can be stored between field capacity and the selected maximum moisture tension should be above permanent wilting percentage.

Answer 58

depth

Question 58

necessary to divert water from a source, convey it to the intended area and control the application or distribution to individual farm lots

Answer 58

Irrigation Structures

Question 58

the process of determining when irrigate and how much water to apply per irrigation. It is essential for efficient use of water, energy and other production inputs such as fertilizers.

Answer 58

Irrigation Scheduling

Question 58

Structures in an open
canal system is subdivided in

Answer 58

1) Headwork structures
2) Conveyance structures
3) Control structures
4) Protective structures
5) Combined structures

Question 58

Structures may be grouped into two categories: those common to gravity irrigation systems such as an _____, and those that are used in pressurized systems such as_______.

Answer 58

open canal network, pipes and sprinklers or drip irrigation systems

Question 58

a) Flumes across channels, drainage course, or depressions;
b) Inverted siphon under obstructions or across drainage courses, or under farm roads;

Answer 58

Conveyance structures

Question 59

a) Spillway to prevent overlapping of canal banks;
b) Over chute to carry flood runoff over open channels;
c) Culvert to carry drainage

Answer 59

Protective structures

Question 59

advantageous to combine checks and turnouts with other structures

Answer 59

Combined structures

Question 59

structures which raises the water level in the river so that water can be diverted through the conveyance canal

Answer 59

Diversion dam

Question 60

structure used to raise water to a desired height to enable water to flow to the headworks of the different canal, branching from the main canal, laterals and sublaterals.

Answer 60

Checkgate

Question 61

– structure which serves as outlet of water in irrigation canals whereby water passes through and discharges into main farm ditch or service area.

Answer 61

Turnout

Question 62

structures to divide the flow of water at desired directions usually placed or built with the main farm ditch to divert water to supplementary
farmditch.

Answer 62

Division box

Question 63

structure which crosses waterways to discharge the excess water drained or removed from the field

Answer 63

Drainage crossing

Question 63

to convey water over the ditch bank into the furrow.

Answer 63

Siphon tubes

Question 63

conveys canal water under roads or railroads. The minimum recommended clearance between the road and culvert for railroad and road crossing is 0.90 m while for farmroad and thresher crossing is 0.60 m if needed.

Answer 63

Road Crossing

Question 63

structure constructed or placed along supplementary farmditch at the head of the internal farmditch to control and regulate water flows serving farm or group of farms.

Answer 63

Off-take

Question 64

are specially shaped, engineered structures that are used to measure the flow of water in open channels.

Answer 64

Flumes

Question 64

structure at the end of a farmditch to check the direct flow of water to the drainage ditch.

Answer 64

End check

Question 64

structure constructed across irrigation canals for traffic crossing by man, animal, cart, sleds, or vehicles.

Answer 64

Canal crossing

Question 65

closed conduit designed to convey canal water in full and under pressure running condition, to convey canal water by gravity under roadways, railways, drainage channels and local depressions.

Answer 65

Inverted siphons

Question 65

to convey water underneath roads or other obstructions

Answer 65

Culvert

Question 65

for places where natural slopes down which canals must flow are so high as to cause excessive water velocities & erosion of the canal banks & bed.

Answer 65

Drops & Chutes

Question 65

used to shorten the length of a diversion canal to avoid difficult & expensive construction on steep, rocky hillsides & to convey water through mountains

Answer 65

Tunnels

Question 65

The method needs a ______ device with a revolution counter that registers the number of rotation of the meter propeller or cup for a given period.

Answer 65

Current meter method

Question 65

This velocity area method is easy and practical to employ in the absence of a flow measuring device

Answer 65

Float method

Question 65

Pumps are hydraulic equipment which may be classified into two types:

Answer 65

a) rotodynamic pumps
b) displacement pumps

Question 65

water conveying conduit or trough which is supported on abutments by piers.

Answer 65

Elevated flume

Question 65

Centrifugal pump requires priming before it is started. ______consists of filling the casing with water so that air trapped does not hinder its operation and reduce its efficiency.

Answer 65

Priming

Question 65

These are the notched opening on structures pace across the canal or creek. They obstruct the flow to create a pond and the water passes over a crest which can be rectangular, triangular or trapezoidal in shape.

Answer 65

Use of sharp crested weirs

Question 66

in-line canal structure designed to convey canal water from a higher level to a lower level, duly dissipating the excess energy resulting from the drop in elevation.

Answer 66

drop

Question 66

with rotating element which imparts energy to water (the action is the reverse of a turbine generating hydroelectric power)

Answer 66

rotodynamic pumps

Question 66

may be used to estimate flood discharge when it is not practical and safe to do direct measurements.

Answer 66

Indirect Measurement Methods

Question 66

especially designed to measure flow by nothing the head loss caused by forcing a stream of water through a throat or constricted section of the flume with a depressed bottom.

Answer 66

Use of Parshall flume

Question 66

The opening can be rectangular or circular in shape.

Answer 66

Use of Orifice Opening

Question 66

include reciprocating type in which a piston draws water into a cylinder on one stroke and forces it out onto the next, and the rotary type which two cams or gears mash together and rotate into opposite directions to force the water continuously past them.

Answer 66

displacement pumps

Question 66

____ means more power cost and more time required to apply the needed irrigation water. Under usual operating conditions centrifugal pumps have efficiencies between 50 and 85%.

Answer 66

Low efficiency

Question 66

a channel built with unvarying cross-section and constant bottom slope; otherwise the channel is nonprismatic

Answer 66

Prismatic channel

Question 66

The overall efficiency of a new electric motor and water pump is about ____. Motor has at least ____ efficiency and the pump about ____.

Answer 66

65%, 95%, 75%

Question 66

refers to the cross section of a channel taken normal to the direction of flow

Answer 66

Channel section

Question 66

refers to the vertical distance at which water is lifted. also referred to a STATIC HEAD

Answer 66

Pumping Lifts

Question 66

a conduit in which water flows with free surface. Open channel can be
Natural channel (UNDERGROUND STREAMS) , which include all watercourses that exist naturally on the earth.

Answer 66

Open channel

Question 67

is the vertical distance of the lowest point of a channel section from the free surface (or depth of flow section, d)

Answer 67

Depth of flow, y

Question 67

the cross-sectional area of the flow normal to the direction of flow

Answer 67

Water area, A

Question 67

the elevation or vertical distance of the free surface above a datum. If the lowest point of the channel section is chosen as the datum, the stage is identical with the depth of flow.

Answer 67

Stage

Question 67

is the width of channel section at the free surface.

Answer 67

Top width, T

Question 68

the sum of the pressure head (p/γ) and elevation head (z). For open channel flow (in which the pressure head is zero), the _______ elevation is the same as the water surface elevation.

Answer 68

hydraulic grade

Question 68

the length of the line of intersection of the channel wetted surface with a cross-sectional plane normal to the direction of flow.

Answer 68

Wetted perimeter, P

Question 69

measuring the mean flow velocity across section and multiplying it by the area at that point to calculate the flow rate.

Answer 69

Velocity-Area Method

Question 70

The rate at which energy is lost along a given length of channel ________and is usually presented as a unitless value or in units of length per length
(ft/ft, m/m, etc.).

Answer 70

friction slope

Question 71

the sum of the hydraulic grade and the velocity head (V^2/2g). This is often referred to as the ________, or EGL. For a lake or reservoir in which the velocity is essentially zero, the EGL is equal to the HGL

Answer 71

energy grade line

Question 72

the flow rate is calculated by weighing the entire content of the flow stream that was collected in a container for a fixed length of time.

Answer 72

Timed Gravimetric Method

Question 73

the flow rate is measured by determining how much the flowing water dilutes an added tracer solution

Answer 73

Dilution Method

Question 73

If F is less than unity, or < square root 𝑔𝐷 , the flow is ______. In this state the role played by gravity forces is more pronounced; so the flow has a low velocity and is often described as tranquil and streaming.

Answer 73

subcritical

Question 74

Flow Measurement in Open Channels

Answer 74

1. Timed Gravimetric Method
2. Dilution Method
3. Velocity-Area Method
4. Hydraulic Structure Method
5. Slope-hydraulic Radius-Area Method

Question 75

if the viscous forces are so strong relative to the inertial forces that viscosity plays a significant part in determining flow behavior.

Answer 75

Laminar flow

Question 75

if the viscous forces are weak relative to the inertial forces.

Answer 75

Turbulent flow

Question 75

mixed state between laminar and turbulent states.

Answer 75

Transitional flow

Question 75

When Froude number is equal to unity (𝑉 = square root 𝑔𝐷) the flow is said to be in a _____

Answer 75

critical state

Question 76

lined channels and built-up channels that can withstand erosion satisfactorily.

Answer 76

Nonerodible Channel

Question 76

If F is greater than unity, or 𝑉 > square root 𝑔𝐷, the flow is _______. In this state the inertial forces become dominant; so the flow has a high velocity and is usually described as rapid, shooting and
torrential.

Answer 76

supercritical

Question 76

The depth of flow must be constant (that is, the hydraulic grade line must be parallel to the channel bed). This depth of flow is called _______.

Answer 76

normal depth

Question 76

an empirical equation widely used for uniform open channel flow

Answer 76

Manning’s Equation

Question 76

velocity distribution in an open-channel flow is quite non-uniform because of (1) non-uniform shear stress along the wetted perimeter, (2) presence of free surface on which the shear stress is zero

Answer 76

Velocity Distribution

Question 76

If the velocity is lower than critical velocity (the depth is greater than critical depth), the flow is ______.

Answer 76

subcritical

Question 76

the vertical distance from the top of the channel to the water surface at the design condition.

Answer 76

Freeboard

Question 76

the velocity is higher than critical velocity (that is, the depth is less than critical depth), the flow is considered

Answer 76

supercritical

Question 77

unlined channels except those excavated in firm foundations, such as rock bed.

Answer 77

Erodible Channel

Question 77

The nonerodible materials used to form the lining of a channel and the body of a built-up channel include

Answer 77

concrete, stone masonry, steel, cast iron, timber, glass, plastic, etc.

Question 77

The purpose of lining a channel is in most cases to _____, but occasionally it may be to check seepage losses.

Answer 77

prevent erosion

Question 78

the channel section having the LEAST WETTED perimeter for a given area has the maximum conveyance; such a section is known as the .

Answer 78

best hydraulic section

Question 78

the speed at which waves will ripple outward from a pebble tossed into the water.

Answer 78

wave celerity

Question 79

is a function of the crop’s evapotranspiration and irrigation efficiency which will account for unavoidable losses during water application. It is also known as the CROP DAILY WATER REQUIREMENT (WR).

Answer 79

daily water use rate

Question 79

a depth for which the specific energy is at a minimum is called the

Answer 79

critical depth.

Question 79

the capacity of the soil to absorb water and it differs from one soil texture to another Suggested

Answer 79

Soil Intake Rate

Question 79

an aide in determining the number of sprinkler heads needed and the required number and length of laterals, manifolds, and mainline pipes

Answer 79

Field Layout

Question 79

______is necessary to make sure that it is capable of
supporting the root system of the crop or crops to be planted. That is, _____ should be greater than or at least equal to the plant root depth.

Answer 79

soil depth

Question 79

the quantity of water, which should be applied during irrigation in order to replenish the water used by the crop during evapotranspiration.

Answer 79

depth of water application

Question 79

_____ requirement of the crop determined by subtracting the rainfall (if any) from the peak daily crop water requirements.

Answer 79

peak daily water use

Question 79

_______ shall be decided based on the extent of field area, source of water and type of sprinkler irrigation system

Answer 79

Sprinkler and lateral spacing

Question 79

the time it takes the crop to deplete the soil moisture at a given soil moisture depletion level.

Answer 79

Irrigation frequency